Elastic-fluid turbine.



1 PATBNTED SEPT. 26, 1905.

W. T. MIXSBLL.

ELASTIC FLUID TURBINE. I APPLICATION FILED M AY 0, 1903. RENEWED FEB.21.1906- 3 SHEETS-SHEET 1.

I A M PATENTED SEPT. 26, 1905.

w, T. MIXSELL.

ELASTIC FLUID TURBINE. APPLICATION FILED MAY 9, 1903. RENEWED FEB.21.1905.

3 SHEETS-SHEET 2.

- PATENTED sEPT.,20, 1905.

W. T. MIXSBLL. ELASTIC FLUID TURBINE.

' APPLICATION FILED MAY 9, 1903. RENEWED FEB. 21.1905.

3 SHEETS-SHEET 3.

Q Q I//////IIIII/A (Z "W////// ///////A sufficient pressure remains toovercome fric- UN TE B AIES' PAT T o EIoE.

WARD TEMPLE MixsELL, OF WASHINGTON, DISTRICT OF COLUMBIA.

' ELASTIC-FLUID TURBINE.

' ings, forming a part of'this specification, and

to the letters of reference marked thereon.

This invention relates to improvements in turbines, and particularlysuch as are designed for converting pressure of an elastic medium intomechanical power, the objects of the in vention being to secure agreater percentage of mechanical power than heretofore obtained inimpulse or reaction or in combined impulse and reaction turbines withthe employment of an elastic medium under pressure.

In carrying the invention into practice the greatest possible momentumis imparted to the elastic medium with the least possible reduction inpressure, the momentum is con;-

verted into mechanical energy without further reduction in pressure orincrease in expan-- sion, and the pressure at which the momentum isconverted into mechanical energy is again utilized to lmpart momentum tothe elastic medium, which momentum is converted into mechanical energywithout further reduction 7 of pressure or increase in expansion, andthis sequence is repeated until practically no fur} ther pressureremains to impart momentum to the medium. 3

I have discovered in the practical application of the present inventionthat if the pres, sure be utilized to impart momentum to the elasticmedium by reduction to a pressure be-. tween fifty and sixty-five percent. (specifically 58 per cent.) of the absolute initial pressure(or ata rate of expansion of 1: 1.624., specifically) and the momentum beconverted into mechanical energy without further red uction'in pressureor increase in expansion and these steps be repeated a number of timesor until no tional and other resistances the total percentage of energyof the elastic medium which may be converted into mechanical'energy isgreater than where the pressure imparts momentum to the medium by asingle, quick,

Specification of Letters Patent.

Patented Sept. 26, 1905.

Application filed May 9, 1903. Renewed'February 21, 1905. I Serial No.246,778.

therefore, be contrasted with that type of turbine wherein the steam orother elastic medium is reduced .in pressure and expanded continuouslyor that type of compound turbine wherein the steam or elastic medium is"carrying into effect the method above set forth,

but may be utilized to good advantage in many types of turbines wheresimplicity, compactness, and a uniform and eflective control aredesired.

In the structure illustrated the several movable elements or sets ofvanes are mounted on a common shaft; but each is in a separate chamber,the chambers being formed by subdividing a relatively large casing orchamber, the several chambers being connected by passages controlled bya valve, whereby all of the passages may be simultaneously opened orclosed.

In the accompanying drawings, Figure l is a vertical section through aturbine embodying the present improvements. Fig. 2 is a section on theline 2 2 of Fig. 1. Fig. 3 is a diagrammatic view of a preferred form ofvane. larger nozzles. Fig. 5 is a diagrammatic View illustrating theproportional increase in the diameter and length of the orifices of thenoz- Like letters of reference in the several fignres indicate the sameparts.

In the apparatus illustrated a casingA is provided preferably anintegral casting, having a cylindrical interior chamber somewhat largerin diameter than the'diameter of the vanewheels and having at one sideavalve-chamber B, which for convenience of construction is tapering orconical, with the larger end toward the exhaust end of the turbine,wherebyithe valve may be ground, to a seat. The cylin Fig. 4 is adetailed view of one of the drical chamber of thecasing A is subdividedinto smaller chambers by partitions O, preferably driven into the samesteam-tight and each having a pro ecting annular peripheral titions areproperly spaced and positioned, it being a comparatively easy matter toregulate the size of the chamber by making the wall 0 of greater or lesswidth. A lining-diaphragm D is preferably provided on the inner side ofeach of the partitions, between which and the partition a packing D, ofnonconducting material, is held to prevent loss of heat by radiation,and the casing may be jacketed for the same purpose. Each partition isformed with a central bearing, preferably having a conical seat (Z, inwhich fits a correspondingly-shaped journal E. The journals are allmounted on the drive-shaft F, preferably being held by friction andsuitably packed by packing Gr, held in place in the journal by a glandg. The journals can move longitudinally on the shaft and will be somoved by the steam-pressure until each finds its seat in its bearing;but the packing will create sufiicient friction to insure the turning ofeach journal with the shaft. The journals will seat steamtight in theirbearings, and the packing will prevent the leakage of steam along theshaft inside of the journals.

The turbine-Wheels H, having the vanes h I thereon, are located one ineach of the chamance with the center of the shaft as an axis it is thedesign of the present construction to provide a means whereby they mayfind their own centers when rotating, and to permit of this there isinterposed between the hub of the 'Wheels and the journals a sleeve,bushing, or

equivalent connecting means K which will yield or be slightlyelastic--as, for instance, asbestos fiber. The hubs of the Wheels may,if desired, be slightly conical or threaded for holding the sleeves orbushings, and the journals may be correspondingly formed. The Wheels maybe connected with the shaft by pins or other means, which will permitthe journals to seat properly in their bearings independently of thewheels and the wheels to find their proper centers of rotation. As shownin the drawings, pins L pass through the wheel-hub and into the shaftwith suflicient play in the shaft to permit of the results stated. Thevanes are preferably of the crosssectional shape shown in Fig. 3 t'. e.,the inner and outer surfaces are arcs of circles eccentric to eachother. Thus the periphery of the wheels may be made in the form of thickrims and the vanes cut therefrom by simple mechanism, the capacity beinggoverned by the depth or width of the rim and depth of the cuts. Afterthe vanes are formed a cover plate or ring M may be secured over theirends to properly direct the steam or elastic medium through the vanes,inasmuch as acousiderable space is preferably left on the inner andunder sides of the same, as shown in Fig. l. The admission-nozzles fordirecting the steam or elastic medium against the vanes are indicated bythe dotted lines N to N, inclusive, Figs. 1 and 5, one of said nozzles,that lettered N, being shown in cross-section in Fig. 2. They are set ata slight right angle to the periphery of the wheels. Thus, as shown, theangle of the nozzles and the set of the vanes are such as to avoidfriction against the rear faces of the vanes and to secure the maximumeffect in bringing the steam or elastic medium to a state of rest as itleaves the vanes, whereby practically its entire momentum is imparted tothe rotating wheel. Said nozzles, which will be hereinafter morespeeifieally described, are supplied through passages O, leading fromthe valve-chamber, and said passages communicate through parts in thevalve with supply-passages, the first one, 0, leading from the source ofpressure-supply and the others, from the next preceding chamber, asshown clearly in Fig. 1. The elastic medium will thus flow through thevalve and first nozzle into the first chamber, thence through the valveand second nozzle into the second chamber, and so on through all of thechambers, and finally to exhaust. With this construction a movement ofthe valve will control or cutoff the pressure from all of the wheelsalike and will maintain pressure in all of the chambers save the last,and if no condensation has taken place in the interim when the valve isreopened a simultaneous'torque is developed by all the wheels instead ofa successive action and loss in refilling the chambers, as would be thecase if a valve for controlling the flow to or from a single one of thechambers were employed. The bore or passages through the nozzles arepreferably cylindrical, and the nozzles are usually of smooth refractorymetal, such as nickel, driven into the passages in the casing, thelatter passages, for convenience, being drilled in from the outer sideof the casing and subsequently plugged. A branch leading from thevalve-chamber and all of the passages both in the valve and casing areof such capacity as not to restrict the flow from the pressure-sumily orfrom the chambers to the nozzles. The area and length of the restrictedpassage in each nozzle control, first, the momentum imparted to theelastic medium as it leaves the nozzle, and,

secondly, the relative pressure in adjacent chambers, and consequentlythe relative pressure which can be available for imparting momentum tothe elastic medium. The nozzles are so proportioned relatively to eachother as to permit onlyof a reduction in pressure to between fifty andsixty-live (preferably approximately fifty-eight) per cent. of theabsolute initial pressure, and for this purpose not only may thepressure in the generator be considered the initial pressure, but

the pressure in each chamber may be considered as the initial pressurein so far as the next succeeding nozzle and chamber are concerned.

' The proportions may be determined by calculation, thus: The increasein diameter of the succeeding nozzles should be as the square root ofthe ratio of expansion, which at fiftyeight, per cent. reduction isapproximately on throughout the series.

1.624, so that the succeeding nozzles to dis charge a similar volume atthe reduced pres' sure should be as 1:1.275,1.275 being the square rootof 1.624. For instance, if the first nozzle is one inch in diameter thesecond should be approximately 1.275 inches, the third approximately1.624 inches, and'so With this rate of reduction in pressure orexpansion of the elastic medium the greatest momentum may be imparted tothe medium with the least possible reduction in pressure, and it isutilized with the greatest efliciency and economy by making therestricted passages of the nozzles of such length without enlargement orcontraction that the expansion or reduction in pressure occurs beforethe medium leaves the said passage, no further expansion or reduction inpressure occurring during the impact of the medium against thereaction-wheel or in its passage through the vanes, subsequent reductionin pressureor expansion only taking place in the next succeedingnozzle'. The length of the passage in the nozzle is therefore such thatthe elastic-medium is delivered to the reaction-wheel at the moment whenthe greatest momentum has been ac.-

quired by the medium and before its acquired aperture.

momentum has been lessened by frictional resistance against'the wall of.the nozzle. The length may be determined empirically or by calculationand should be approximately 1.624 times the diameter of the nozzle- Toprevent eddying or consumption of energy by friction, the approaches tothe nozzles should be curved in accordance with the well-known lawsgoverning the flow of one pound of steam at a velocity of four-- teenhundred and forty feet per second, as is obtained by afifty-eight-per-cent. reductionthrough each nozzle delivered on thevanes of the wheels equal to thirty-two thousand two 6' hundred andthirty-eight foot-pounds,-(theoretically,) the total for six expansions,being one hundred and ninety-three thousand four hundred andtwenty-eight foot-pounds, oratthe rate of 10.24 pounds of steam perhorsepower per hour, or this same engine can utilize steam at onehundred and fifty pounds pressure absolute, with the same efficiency re-:ducing the pressure throughsix expansions,

as one hundred and fifty to eighty-seven, &c., pounds, generating thesame energy-one hundred and ninety-three thousand four hundred andtwenty-eight foot-pounds, as in the-former series of expansions fromthree hundred and ninety pounds absolute to atmospheric pressure.Thereas'on thatfifty-eight-per-cent. reduction of pressure induces sucha high velocity for the diiference of pressure isthat the maximum"pressure that will exist in a I nozzle isfifty-eight per cent. of theinitial pressure for any reduction of pressure ex-- ternal to the nozzleof fifty-eight per cent. or less. Consequently it becomes necessary whena ,greaterrate of reduction is employed to make the nozzle outwardlydiverging, so as 'toincrease the specific area of the nozzles,

mentum of a single velocity, which might be acquired if the initialvelocity could be augmented proportionately to the absolute ratio ofexpansion.

Fig. 5 shows approximately the proportions of the nozzles for? sixexpansions of the steam, and from this figure it will be seen that eachnozzleis of the same proportions, and throughout its effective part theWalls are approximately cylindrical.

Inasmuch as efiiciency requires that the di-v ameter and length of thenozzles should be coordinated-and as'it is impracticable to vary; thesedimensions uniformly and in unison, separate sets of nozzles arepreferably provided forgiving the diiferentpowers desired and a reverseset or sets of nozzles may beprovided for reversing the'direction ofrotation of the reaction-wheels." Thus in Fig. 2 it will be seen that asecond set of nozzles -O is providedof less length and diameter than thefirst set, and consequently delivering a less weight of steam inaiigiven time, although IIO the pressures in the "generator and severalchambers will remain as before. The valve has its passages so disposedthat one set of nozzles is cut out and the other in when it is desiredto vary the power, and consequently thesteam will be used at the highesteificiency throughout the whole range of expan- 'sion' regardless ofwhether the mechanical ment of as many nozzles as desired, avoids anycomplication of ducts for the reception of the steam passing from thevanes, and also prevents loss due to the escape of pressure betweennozzles and vanes, as such pressure combines with that in the chamberand is available in the next nozzle of the series.

It will be particularly noted that the mechanical construction isexceedingly simple and compact, and the bearings are self-adjust ing inthat the journals are held to their seats by the pressure in thechambers, and wear will not cause .a leakage from a chamber of higherinto a chamber of lower pressure.

The upper surfaces of the partitions C are preferably slightly convex,so as to permit the water of condensation to stand around theshaft-bearings for the purpose of lubrication. The inclination ispreferably very slight, as will be seen by reference to Fig. 1, wherethe top surfaces of the partitions are slightly lower at S than at S.

Having thus described myinvention, what I claim as new, and desire tosecure by Letters Patent, is

1. In an elastic-fluid turbine, the combination of a series ofrelatively short substantially cylindrical nozzles adapted to receivethe elastic fluid in succession, the relation of the length to thediameter of the aperture of each nozzle being uniform in all the nozzlesto permit of uniform reductions of pressure in the nozzles, thesucceeding nozzles in the series being of increased length and increaseddiameter to impart uniform velocity to the same weight but increasedvolume of the elastic medium, a separate chamber of relatively largecapacity for receiving the discharge from each nozzle and from which theelastic medium is delivered to the next nozzle of the series and a setof movable vanes in each chamber against which the elastic medium isdelivered by the nozzle for converting the momentum of the medium intomechanical energy; substantially as described.

2. In an elastic-fluid turbine, the combination with a series ofchambers of successivelyincreasing capacity, a set of movable vaneslocated in each chamber for converting the momentum of the elastic fluidinto mechanical energy, of relatively short substantially cylindricalnozzles located in position to direct the elastic fluid against andthrough between the vanes into the chambers, the relation of the lengthto the diameter of the aperture of each nozzle being uniform in all thenozzles to permit of uniform reductions in pressure in the nozzles, thesucceeding nozzles in the series being of increased length and increaseddiameter to impart uniform velocity to the same weight but increasedvolume of elastic fluid, adjacent nozzles of the series respectively onedischarging into and the other receiving the elastic medium from thesame chamber; substantially as described.

3. In an elastic-fluid turbine, the combination with a series ofchambers of successivelyincreasing capacity, a set of movable vaneslocated in each chamber for converting the momentum of the elastic fluidinto mechanical energy, of nozzles located in position to direct theelastic fluid inwardly into said chambers and against the movable vanes,the relation of the length to the diameter of the aperture of eachnozzle being uniform in all the nozzles to permit of uniform reductionsin pressure in the nozzles, the succeeding nozzles in the series beingof increased length and increased diameter to impart uniform velocity tothe same weight but increased volume of elastic fluid, a passageextending from each chamber through a valve to the next nozzle of theseries, said passages being of greater capacity than the nozzle to whichit extends; substantially as described.

4. In an elastic-fluid turbine, the combination with a series of nozzlesadapted to receive the elastic fluid in succession, the relation of thelength to the diameter of the apertures of each nozzle being uniform inall the nozzles, the succeeding nozzles in the series, being ofincreased length and increased diameter and separate sets of movablevanes for converting the momentum of the fluid into mechanical energy,of a second and correspondingly-proportioned series of smaller nozzlesfor delivering decreased volumes of elastic fluid but at the samevelocity to the vanes and valve mechanism for simultaneously cutting outor in all of the nozzles of either series; substantially as described.

5. In an elastic-fluid turbine, the combination with the casing havingthe cylindrical interior, the series of diaphragms having peripheralflanges, fitting in said casing and resting one on the other to form aseries of chambers, and vaned wheels located in said chambers on a shaftcommon to all the wheels, of an inwardly-directed nozzle opening intoeach chamber and a passage leading from each chamber remote from thevanes to the nozzle of the next succeeding chamber; substantially asdescribed.

6. In an elastic turbine the combination with the series of chambers, ashaft extending through said chambers, a vaned wheel on the shaft ineach of the chambers and a cone-journal for the shaft in each of thechambers on the side toward the adjacent chamber of lower pressure andheld to its seat by the pressure of the elastic fluid in the chamber;substantially as described.

7. In an elastic-fluid turbine the combination with the series ofchambers shaft passing through all of said chambers, vaned wheelsmounted on said shaft and nozzles for directing the elasticmediumagainst the vanes and into the chamber, of cone journals for the shafthaving their bearings in the walls of the chambers and capable of amovement longitudinally of the shaft, whereby each journal is held toits seat and escape of fluid prevented by the pressure Within thechamber; substantially as described.

8. In an elastic-fluid turbine, the combination with the series ofchambers, shaft'passing through all of said chambers, vaned wheels vmounted on said shaft and nozzles for directing the elastic fluidagainst the vanes and into the chambers, ofcone-journals having bearingsin the walls of the chamber, and packing interposed between the journalsand shaft, said journals being movable longitudinally independently ofthe shaft and of each other; substantially as described. 7

9. In an elastic-fluid turbine the combinati'on with the series ofadjacent chambers for receiving the fluid successively, a shaftextending through said chambers and a vaned wheel in each chambermounted on the shaft, of a journal movable longitudinally on the shaftlocated in each chamber and having a bearing in the wall of the chambertoward the next succeeding chamber of the series; substantially asdescribed.

10. In an elastic-fluid turbine the combinationwith the series ofadjacent chambers located one above the other and having their bottomwalls inclined toward the center, of a vertical shaft extending throughsaid chambers, and journaled in said chamber-walls,

vaned wheels on the shaft, inlet-nozzles forv directing the elasticfluid against the vanes and passages for the discharge of the elasticfluid; substantially as described.

WARD TEMPLE MIXSELL.

Witnesses: I

ALEXANDER S. STEWART, MELVILLE D. CHURCH.

